How Can I surf a web site anonymously

Hi,

To protect myself from spammers, is there a way to surf or download a file from a web site?
If yes how?

How do I keep my e mail address private when sending an e mail to an yahoo or hotmail address for some information? Because they can click "Header" to get your e mail & IP address. How do you avoid this? I see many posts where there is no senders e mail address. How do they do it?

Thank You,
Greg

Are there any software for that too?

Thank You,
Sean